Automatic train-stop device.



A. ENGLAND.

AUTOMATIC TRAIN STOP DEVICE.

APPLIOATION FILED OUT. 31, 1911.

1, 1 04,787, Patented July 28, 1914.

INVENTOR WITNESSES THE NORRIS PETERS (20.. PHOTO-LITHQ, WASHINGTON, D4

priinp STATES TENT ornion.

ALEXANDER ENG-LAND, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A

CORPORATION OF PENNSYLVANIA.

AUTOMATIC TRAIN-STOP DEVICE.

mower.

Specification of Letters Patent.

Patented July 28, 1914..

Application filed October 31. 1911. Serial No. 657,728.

The principal object of my invention is to provide an improved trip valve device which is positive in action and compact in construction.

In the accompanying drawing, the single figure is a central sectional view of a trip valve device embodying my invention.

My invention relates more particularly to a vent valve device of the type embodying a main train pipe vent valve, a piston for operating the same, and an auxiliary or pilot valve operated bythe track mechanism for varying the pressure on the piston to effect the opening of the vent valve.

As shown in the drawing. the "entvalve device may comprise a casing 1 having a valve chamber 2, open to the train pipe 3 and containing the main train pipe vent valve 4:. For operating the vent valve 1, a piston 5 is provided which is subiect on one side to the atmospheric pressure of a chamber 6, constantly open to the atmosphere through an exhaust passage 7. Mounted in the piston 5 is a pilot or auxiliary valve 8 adapted to control communication from a chamber 9 to chamber 10 below the piston 5. The chamber 9 is constantly open to the train pipe 3 through a passage 11 in the valve stem 12. The pilot valve 8 is provided with a stem 13 adapted to be actuated by the vertical movement of a trip 14 which, in turn, is adapted to be operated by the track mechanism in any desired manner.

lVhile the trip 14, illustrated in the drawing, is of the vertically reciprocating type, it will be understood that the ordinary swinging trip may be employed, if desired.

The auxiliary valve 8 is subject to the pressure of a light spring 15 which'normally holds the valve to its seat, and the main vent valve 4 is subject to the pressure of a spring 16 tending to hold the same to its seat.

In operation, when the train pipe "is charged with fluid under pressure the chamber 9 also contains fluid under train pipe pressure. The chamber 10, below the piston 5, is normally at atmospheric pressure,

as any fluid pressure leaking into said chamber will escape around the piston 5 to the chamber 6 and the exhaust outlet 7, piston 5 being a loose fit in its bore. If the trip 14, however, is operated by the track mechanism, the valve stem 13 is actuated by the movement of the trip 14 to lift the pilot valve 8 from its seat and fluid from the train pipe is thereupon supplied to chamber 10 below the piston 5. The opposite side of the piston being at the atmospheric pressure of the chamber 6, ex-

cept for the seated area of the, vent valve 4, the piston 5 is actuated by the admission of the train pipe pressure to the chamber 10 and the main train pipe vent valve 4 is thereupon lifted from its seat to vent air from the train pipe.

In order to maintain the main vent valve open for a suliicient length of time to vent the desired amount of air from the brake pipe, I have provided means for maintaining the pilot valve 8 oil its seat upon move ment of the piston 5. For this purpose an arm 17 pivoted to piston 5 is provided. One end of the arm is adapted to engage a fixed part of the casing 1, while the other end of the arm is adapted, upon upward movement of the piston 5, to engage a collar 18 on the valve stem 13. It will now be evident that, upon the upward movement of the piston 5, the arm 17 will be rocked on its pivot and the valve 8 W111 be malntained off its seat by the engagement of one end of the arm 17 with the shoulder 18.

The time that the main vent valve re-. mains open is dependent on the spr1 ng 16 and the train pipe pressure acting in the chamber 10 on the piston 5, and as soon as the train pipe pressure falls below the pressure of the spring 16, the piston 5 and the main vent valve 4 are shifted downwardly by the spring 16 to cut off further yenting of air from the train pipe. The downward movement of the piston 5 also allows the arm 17 to release the vent valve 8 so that spring 15 operates to return the pilot valve to its seat.

By means of the present construction, the trip valve device is rendered positive in its action, as the same Will not be aflected by any ordinary leakage past the valve and, as the vent valve piston is positively operated by admitting fluid pressure to one side, the prompt movement of the train pipe vent valve 4 is always assured.

Having now described my invention, What I claim as new and desire to secure by Letters Patent, is

1. The combination With a train brake pipe, of a main valve for venting air from said brake pipe, a piston normally subject on opposite sides to atmospheric pressure for operating said valve, and an auxiliary valve mounted in said piston for vent-ing air from the brake pipe to one side of said piston to thereby open said main valve.

2. The combination with a train brake pipe, of a main valvefor venting air from said brake pipe, a piston normally subject on opposite sides to atmospheric pressure for operating said valve, an auxiliary valve having a seat in said piston for venting air from the train brake pipe to one side of said piston, and a spring acting on said piston in opposition to the brake pipe pressure to close the main valve upon a predetermined reduction in brake pipe pressure.

3. A valve device for air brakes comprising a main vent valve, a piston for operating said valve, a pilot valve for varying the pressure on said piston, and means controlled by the piston for maintaining the pilot valve open.

4. A valve device for air brakes comprising a main vent valve, a piston for operating said valve, a pilot valve adapted to be initially opened for varying the pressure on said piston, and means operated by said piston for maintaining said pilot valve open While the piston is in its open position.

5. A valve device for air brakes comprising a main vent valve, a piston for operating said valve, a pilot valve adapted to be initially opened for varying the pressure on said piston, and a pivoted arm adapted upon movement of the piston to contact with a fixed abutment at one end, thereby rocking the arm to eiiect the movement of the pilot valve by operative engagement of the opposite end with said valve.

In testimony whereof I have hereunto set my hand.

ALEIXL LNDER ENGLAND. WVitnesses A. M. CLEMENTS, T. L. RAFTERY.

copies of thil patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

